Get set for invisible war machines

Defense contractor BAE Systems is working on an optical camouflage technology that will make tanks and other vehicles blend in with their surroundings.

Within a few years the Brits may deploy invisible armored tanks onto the battlefield, a breakthrough in stealth technology that Harry Potter would certainly applaud.

Defense contractor BAE Systems is working on the technology, which uses a "display system within the structure of the vehicle" to display images captured by cameras on one side of the vehicle on the opposite side so that the vehicle "blends in with the background scenery," company spokesman Mike Sweeney explained to me today.

"We also have a way to protect that structure from battle damage and that's obviously key," he added.

The images would be constantly updated, keeping the tank camouflaged as it rolls through the landscape.

Optical camouflageThe concept of wrapping a vehicle or person in real-time images of its surroundings has been worked on for years. An optical camouflage jacket developed by Susumu Tachi and his colleagues at the University of Tokyo, for example, made the Internet rounds in the mid-2000s.

"Pretty much all the systems that have been cooked up so far all use a projector that picks up the background," Sweeney said. "Where they differ is in how the image is then displayed."

He is tight-lipped on the details of BAE's display system, called eCamouflage, but said to think in terms of something like a flat screen television. This would make displays work relatively easily on flat surfaces, such as depicted in the concept image of the tank above. "I honestly don't know how we are doing it on other areas" such as the front of the tank, Sweeney added, though he noted that is indeed the plan.

Invisible subs?When the invisible tanks start rolling on the battlefield, the Navy, too, may be deploying submarines outfitted with technology that makes them invisible to sonar, according to researchers at the University of Illinois. In the journal Physical Review Letters, they reported the successful testing of a prototype acoustic cloak.

The device is made up of a specially engineered material molded into a series of concentric rings that looks similar to a record or compact disc. When an object is placed in the center of the cloak and submerged under water, sound waves hit the cloak and travel around to the other side, completely bypassing the object.

"The acoustic wave will travel through the channels because it's easier to travel through there," mechanical engineer Nicolas Fang explained to Medill Reports. "So if we use an array of those channels, the moment sound hits the cylindrical structure, it will travel around the shell instead of traveling through."

The next step is to make this cloaking structure flexible — a fabric or even a paint that refracts sound waves. The paint could then be used to coat a submarine, making it invisible to sonar.

"How can we make it a paint?" Fang asks. "I would consider this more of an engineering issue than a fundamental challenge."